1. Field of the Invention
The invention is directed to a mechanism for releasable fastening of a drum fashioned as intermediate carrier of a non-mechanical printer or copier device.
2. Description of the Prior Art
A prior art mechanism is disclosed by German published application 27 17 055 and corresponding U.S. Pat. No. 4,134,669 . In that mechanism, the photo-conductive drum includes turned-out cylindrical carriers at both ends that cooperate with corresponding necks of drum receptacle flanges that are arranged on the drive shaft. One drum receptacle flange is rigidly connected to the drive shaft while other can be detachably slipped onto the drive shaft via a through bore. A clamp mechanism that is screwed to the drive shaft presses the releasable drum receptacle flange resiliently against the drum which is then pressed against the stationary drum receptacle flange.
The concentric running precision of the photo-conductive drum that can be obtained with such a mechanism is dependent on the differential play between the drum receptacle flanges and the inside diameter of the photo-conductive drum, on the differential play between the through bore of the releasable drum receptacle flange and the drive shaft and on the actual concentricity precision of the drive shaft.
In printer equipment operating with intermediate carriers, such as electro-photographic printer equipment or magnetic printer equipment, a high concentricity precision of the drum-like intermediate carrier is extremely important for good print quality. This is particularly true when printing is to be carried out with a high character resolution. When a number of printed apparatuses are coupled together to produce multi-color printing or front and backside printing, the concentricity precisions of each printer apparatus participating in the printing add up.